Mycorrhizal tree dominance effects on community-level nutrient status and resorption efficiency depend on tree...

Tree mycorrhizal type and tree species diversity are pivotal drivers of nutrient contents and resorption of individual plants. However, it is unclear how community-level nutrient status and resorption will change along mycorrhizal tree dominance, in particular how the trends vary with tree diversity. We investigated the impacts of arbuscular mycorrhizal tree dominance (AMD) nested with tree species richness (SR) on the community-level leaf and litter carbon (C), nitrogen (N) and phosphorus (P) contents, stoichiometric ratios, and N resorption efficiency (NRE) and P resorption efficiency (PRE), and soil available nutrient status. Our results showed that leaf and litter C and N contents and C:P and N:P ratios generally declined, but leaf P content, and nutrient resorption efficiencies (i.e., NRE, PRE and NRE:PRE ratio) increased with increasing AMD. Moreover, soil inorganic N (i.e., NH4+-N and NO3--N) and available P contents declined with increasing AMD. Our findings demonstrated that the effects of AMD on plant and soil nutrient status varied with tree SR, showing amplified effects of AMD on plant nutrient status and weaken effects on soil available nutrient and plant nutrient resorption in high-diverse community. In addition, we conclude that the 'nutrient concentration control' is the key driving mechanism of leaf NRE, but 'stoichiometry control' is a main regulator of PRE in subtropical forests. Our results provide a guidance of using mycorrhizae-associated tree species to achieve more available nutrient resources and thereby improving productivity in mixture plantations.